1. Field of the Invention
The present invention relates to a back wiring board and an aggregated device of back wiring boards, and in particular to a back wiring board which connects a printed board package mounted thereon to testing equipments (testers) and an aggregated device thereof.
In recent years, an electronic device has been required to have not only a high-performance and a high-quality but also a low price and a compactness. In order to reduce the price of e.g. a switchboard system in its entirety and to compact same, the connection and the arrangement of units such as a subscriber circuit unit and a testing unit are important constitutional elements.
2. Related Prior Art
FIG. 17 shows an arrangement (1) of a switchboard system having the prior art back wiring board as a component. This switchboard system is mainly composed of a communication channel system, a central processing system, and an I/O system.
The communication channel system has a subscriber circuit (SLC) shelf 210 connected to telephones 100a-100n. The central processing system has a switching unit (SW) 400 connected to the subscriber circuit shelf 210 and a central processing unit (CC) 410 connected to the switching unit 400. The I/O system has a terminal equipment 420 connected to the central processing unit 410.
The subscriber circuit shelf 210 is composed of subscriber circuit units 212a-212n respectively connected to the telephones 100a-100n, a selector 211 connected in parallel with the subscriber circuit units 212a-212n by means of a conductor pattern PP on a back wiring board (not shown), and a common line trunk 214 connected to the subscriber circuit units 212a-212n and the selector 211 through the back wiring board and connected to the switching unit 400.
A jumper terminal frame (JPTF) is connected to the selector 211 through connectors CNa, CNb with a cable CBL, and is connected to testers 300a-300m through a cable CBL1.
The subscriber circuit units 212a-212n are respectively composed of relays RL1, RL2 respectively connected in cascade connection to the telephones 100a-100n and a subscriber circuit (SLC) 2121. The relays RL1, RL2 are connected to the selector 211 through the conductor pattern PP on the back wiring board. The selector 211 is composed of relays RL3, RL4 selectively connecting the conductor pattern PP to the connectors CNa, CNb.
In operation, the relays RL1, RL2 are normally preset so that the telephones 100a-100n may be respectively connected to the subscriber circuit 2121 in each of the subscriber circuit units 212a-212n.
When the subscriber circuit unit 212n is to be tested or examined with the tester 300m as one example, a terminal connected to the tester 300m is connected to a terminal connected to the selector 211 by means of lapping in the jumper terminal frame 900. After the connection, the terminal equipment 420 transmits a test demand signal to the subscriber circuit unit 212n and the selector 211 through the central processing unit 410, the switching portion 400, and the common line trunk 214.
In response to the test demand signal, the subscriber circuit unit 212n disconnects the telephone 100n from the subscriber circuit 2121 and switches over the relays RL1, RL2 so that the telephone 100n and the subscriber circuit 2121 as disconnected may be connected to the conductor pattern PP on the back wiring board. Also, in response to the test demand signal, the selector 211 properly turns on the relays RL3, RL4 so that the conductor pattern PP may be connected to the tester 300m through the jumper terminal frame 900.
As a result, the tester 300m is now connected to the telephone 100n and the subscriber circuit 2121 of the subscriber circuit unit 212n. After the execution of a predetermined test, the tester 300m transmits the test result to the terminal equipment 420 through the switching portion 400 and the central processing unit 410.
FIG. 18 shows an arrangement (2) of such a switchboard having the prior art back wiring board and the aggregated device thereof as components.
In this arrangement (2), different from the arrangement (1) of FIG. 17, the back wiring board (not shown) mounting the selector 211 within each of the subscriber circuit shelves 210a-210j and the back wiring board (not shown) mounting the selector 211 within each of the subscriber circuit shelves 210k-210p form selection groups 200a, 200b which are respectively the aggregated devices of the back wiring boards.
Also, different from the arrangement (1), the selectors 211 within the subscriber circuit shelves 210a-210j and the jumper terminal frame 900a are mutually connected with a cable CBLa through the connectors CNa, CNb, and the selectors 211 within the subscriber circuit shelves 210k-210p and the jumper terminal frame 900b are mutually connected with a cable CBLb through the connectors CNa, CNb.
In operation when the subscriber circuit 2121 and the telephone 100 (see FIG. 17) connected to the selector 211 in the subscriber circuit shelf 210p in the selection group 200b are tested by the tester 100m as an example, after the connection by the jumper terminal frame 900b, the tester 300m is connected to the telephone 100 and the subscriber circuit 2121 disconnected as above-noted through the cable CBL1b, the jumper terminal frame 900b, and the cable CBLb.
As a result, the tester 300m is capable of testing the telephone 100 and the subscriber circuit 2121. Likewise, the other subscriber circuits 2121 in the selection group 200b can be tested with any one of the testers 300a-300m.
Namely, in the selection group 200b, the testers 300a-300m can be commonly used for the subscriber circuits within the subscriber circuit units.
Also in the selection group 200a, the testers 300a-300m belonging to this selection group 200a can be connected to the subscriber circuits 2121 belonging to the shelves 210a-210j through the cable CBL1a, the jumper terminal frame 900a, and the cable CBLa to perform the test.
FIG. 19A shows a mounted example of shelves in the prior art switchboard, which are composed of two control system shelves 230, five subscriber circuit shelves 210, and a single jumper terminal frame shelf 900.
Such a switchboard having the prior art back wiring board and the aggregated device as the components requires the jumper terminal frame 900 (see FIG. 19A) between the selector connected to the subscriber circuit and the testers, as shown in FIGS. 17 and 18, in order to test the subscriber circuits.
The jumper terminal frame 900 has a subject of compactness due to the occupation of a certain mounting space.
Also, the connection in the jumper terminal frame 900 possibly becomes erroneous because a maintenance person does so manually by means of lapping etc.
Moreover, each of the selection groups as shown in FIG. 18 have 2000-3000 subscriber lines so that it is necessary to connect at least one tester of a high-price and a high-performance in addition to relatively cheap testers of a simple performance to the selection groups.